Neosporosis is an infection caused by the protozoan parasite Neospora caninum and is an infection of cattle worldwide. This microscopic parasite is the most frequent cause of bovine abortions in many countries. The parasite is believed to have as life cycle where infection can occur in utero or ingestion of it's infectious particles (oocysts) in the feces of a definitive host (possibly dogs).
Congenital (before birth) infection is a means of perpetuation of the disease in some herds; live born calves from congenitally infected cows are believed to be life long infected. In other cases, a point source of exposure can be determined, thereby suggesting spread of the infectious agent by a definitive host (possibly a cat or dog).
Abortion is the only clinical sign observed in infected cows. Abortion typically occurs between 4 and 8 months of gestation. Fetuses may die in utero, be reabsorbed, mummified, born alive but infected or born clinically normal but chronically infected. A presumptive diagnosis could be made when faced with an abortion outbreak on farm. HOWEVER, OTHER CAUSES OF BOVINE ABORTION MUST ALSO BE CONSIDERED. The diagnosis may be confirmed by serological examination of a sample from the dam and or aborted fetus (where possible).
Currently, there is no recognised method for infection control from the (unknown) definitive host. Assuming it must be a carnivore or scavenger, all efforts should be directed to excluding the possibility of:
1. Fecal contamination of cattle feed by (cats or dogs)
2. Fetal membranes, fluids, aborted fetuses and dead calves should all be removed so that any putative definitive host and or cattle cannot access them.
3. Congenitally infected cows are at high risk of abortion and abortion rates can be reduced by culling these animals.
HYGIENE AROUND CALVING TIME AND PREVENTION OF CONTACT WITH "POTENTIALLY DANGEROUS DOGS" ON YOUR FARM ARE VITAL STEPS IN THE PREVENTION OF DISEASE